Methods

The study was sponsored by the University of East Anglia (UEA) and funded by the Anthony Long and Bernice Bibby Trusts. Ethical approval was granted by the Oxford C Research Ethics Committee (Ref: 07/H0606/100).

Study Design

Participants and Data Sources

Prospective participants were identified for recruitment at ENT outpatient clinics at 30 participating centres. Patients with CRS were examined by an ENT clinician and classified into different CRS phenotypes; chronic rhinosinusitis without polyps (CRSsNPs), chronic rhinosinusitis with nasal polyps (CRSwNPs) or allergic fungal rhinosinusitis (AFRS) as per EPOS 2012 criteria16 (see CRS participant section below). Healthy controls were recruited from family members of patients attending ENT clinics as well as members of hospital staff at recruitment sites.
Questionnaires were completed during the clinic visit or taken home to be completed and returned by prepaid post. No participant identifiable data was captured therefore consent was not required although it was implied through return of the questionnaire. Returned questionnaires were scanned and the data imported into in an electronic database in Microsoft Excel. Records in the database were compared to physical copies of the questionnaires by two members of the research team to ensure accuracy and consistency between the two.
All CRS participants and healthy controls were required to meet the inclusion/ exclusion criteria outlined below:

CRS Participants

Inclusion Criteria
Criteria for diagnosis of CRS with or without polyps (EPOS guidelines)16
At least two symptoms must be present for at least 12 weeks and include:
and additionally:
Patients were then classified as having CRSwNPs, CRSsNPs or AFRS. Those patients with the latter additionally adhered to either the Bent and Kuhn criteria17or the modified Vancouver criteria.18

Healthy Control Participants

Exclusion Criteria

Exclusion Criteria for Both Groups

Quantitative Variables and Bias

A specific question on smoking was included in the questionnaire as follows: